Military airplane



l Nov. 17,1942. J. HEITMANN 2,302,629

MILITARY AIRPLANE Filed Dec.- '7, 1940 2 Sheets-Sheet 1 INVENTOK .fof/N /ff/rM/Mw i7, 12- J. HEITMANN 2,362152@ MILITARY MRPLANE Filed Dec. f2', 194.0 2 Sheets-Sheet 2 A f ZNVENTOR y I d0/1A Hanf/,wma

Patented Nov. l?,

UNITED STATES PATENT OFFICE 2,302,629 MILITARY AIRPLAN'E John Heitmann, Brooklyn, N. Y.

Application December 7, 1940, Serial No. 369,073

7 Claims.

This invention relates to aircraft generally, but more particularly to airplanes suitable for military use, and aims to provide an airplane having the features and advantages herein set I forth.

One of the objects of the invention is the provision of such an airplane with a bullet-proof or absorbing coating covering all of the exposed surfaces of the craft, to prevent bullets from machine guns or other smal1 caliber arms from penetrating the surface of the plane.

Another object is the provision of passenger or troop-carrying compartments provided with doors of the general trap door type which may be opened by the pilot to let the troops out, from a position above the ground or` on the ground, in a minimum interval of time.

A further object is the proviison of means operable by the pilot for slowing down the plane just above the ground to such a degree .that the troops may safely be let out through the abovementioned doors, without necessitating stopping of the plane or landing thereof.

A still further object is the provision of means whereby the plane may be propelled on land in a sidewise direction so as to be able to get into a. narrow space such as a clearing, for example.

Other objects as well as the above will be more clearly set forthv in the description below, reference being had to the accompanying drawings wherein the reference numerals indicate parts referred to in` the description. Although the drawings illustrate a land plane, the invention is as readily adaptable to a'sea plane or to an autogyro, and it is not desired to limit the same in any way to a particular type of plane.

Referring' briey to the drawings,

Figure 1 is a plan view of the airplane, with parts broken away.

Figure 2 is a cross-sectional view taken on the line 2--2 of Figure 1.

Figure 3 is a cross-sectional View taken on the line 3w3 of Figure 1.

Figure 4 is a cross-sectional view taken on the line 4-4 of Figure 1. i

Figure 5 is a cross-sectional view taken on the line :5 5 of Figure 4.

Figure 6 is a substantially enlarged crosssectional view taken on the line 56 of Figure 1.

Figure 7 is a cross-sectional view taken on the line I-I of Figure 6.

Figure 8 is a cross-sectional view taken on the line 8-8 of Figure 2.

Figure 9 is a fragmentary plan view of the plane, illustrating the means for tilting th rear wing tips.

Figure 10 is a cross-sectional view taken on the line Ill-I0 of Figure 9.

Figure 11 is a cross-sectional view taken on the line II--II of Figure 9.

Figure l2 is a cross-sectional view taken on the line I2--I2 of Figure 9.

Figure 13 is a front view of the wings tip actuating mechanism shown in Figure 9, per se.

Figure 14 is a fragmentary underside plan view, partly in section, of the plane body.

Referring in detail to the drawings, the numeral I0 indicates the body or fuselage of the plane and the numerals II the wings, the propeller being s hown at I2 and the twin tails at I3. By means of vertical partitions, the inner Wing sections are divided into two compartments on each dde of the, body I0, shown at I5, and two additional compartments I4 just beyond the compartments I5. By means of holes I6, these compartments communicate with each other and with the pilots cabin Il.

Each compartment I4 and I5 has a trap door I8 hinged at its forward end to the lower wing surface, and when closed it lies flush with that surface. Each of the partitions above-men tioned is composed of an upper fixed section I9 and a lower complementary section 20 which is xed to the door I8 and drops with the latter when the door is opened. The inter-compartmental openings I5 are formed by complementary substantially semi-circular openings in the fixed and stationary partitions` as is obvious.

A gun turret compartment 2I is formed forward of each pair of compartments I4 and is provided with an extension ladder drop or trap door, 22 by means of which access and exit may be had from the ground. Escape manholes 23 are provided forward of each of the compartments I5. The doors I8 are adapted to be let down simultaneously by the pilot, by means of the following mechanism. A hand wheel 24 in the pilots cabin is xed to a horizontal shaft 21. Each compartment has an upright shaft 25 bevel-geared to the shaft 21 and provided with a worm 26. A continuous shaft 26a extends on each side of the plane and serves as a hinge for all of the doors I8 on that side. In each compartment I5--I4 the shaft 26a has a gear sector 28 secured thereto, the latter being also fixed "to the door. Thus, upon rotation of the shaft 21 all of the doors I8 are simultaneously raised or lowered.

The rear wing tips 29 are pivoted to the fixed 'forward wing tips 3l by hinges 30. A vertical arm or yoke 32 is fixed to the tip 29, and its extremities are joined by wires 33 to the ends of a parallel but shorter yoke 34 fixed on a bevel gear 35. The latter meshes with a bevel gear 36 having rigidl and parallel therewith a wheel 31 about which a cable 38 is trained. This cable passes, at its other end, over a wheel having the' bevel gear 39 fixed thereto, the latter meshing with a bevel gear 40 on the end of a shaft 4| provided with a handle .42 located in the pilots cabin and adapted to be operated by him to tilt or straighten the wing tips 29 as desired. The same mechanism is used on both sides of the plane for both wing tips 29, and theyl are both operated simultaneously. 1t is to be noted that themechanism for opening and closing the doors I8 as well as that just described for tilting the wing tips 29, is presented for purposes of illustration only and it is not necessarily intended that those mechanisms be used.

Each of the wing tips 29 is provided with 'a transverse cut-out 43 to accommodate a push propeller 44 adapted to rotate in a plane at right angles to that ofvthe main propeller I2. By means of the bevel gea'rs and shaft shown generally at 45, the propeller 44 is rotated by a shaft 46 in axial alignment with the hinge 30. By means of bevel gears the shaft 46 is driven by an auxiliary motor 41 situated in the body I0. The pilot's controls for the motor 41 are not shown, as they may be provided in an obvious manner. Likewise a clutch, now shown, may be used to shift the shaft 48, leading to the other -wing 29, into engagement with the motor 41 while shifting the shaft 46 out of engagement, and vice versa, and also for maintaining both shafts out of engagement with the motor; the latter is the normal condition. It is apparent that, regardless of the amount of tilt to the wing tips 29, either auxiliary propeller 44 may be set in motion. In 'order that the auxiliary propeller may more readily propel the plane on the ground in a sidewise direction, the landing gear yoke 49 may be pivoted to the body I by interposing a plate U therebetween and providing a pair of .spaced holes 5| through the bridge of the yoke and similar holes, not shown, in the plate 50.l

Screws, pins, or any other means may be set into the aligned holes to maintain the gear in its normal position with the yoke at right angles to the normal direction of travel in the air. These may be removed when it is desired to propel the plane sidewise on the ground to give thelanding gear the same freedom of rotation as a caster. The tail gear wheel 52 is likewise provided as a caster.

To make the outer surfaces of the plane bulletproof, a coating of relatively soft rubber 53, having itself a skin of relatively harder rubber 54 on both sides, is provided on all the said surfaces. Imbedded in the rubber 53 is a network of interlocking coiled springs. Small caliber bullets which pierce the outer and soft rubber will be resisted and diverted by contact with the springs 55, and will fail to pass through the coating into the plane surfaces.

The yplane has many uses for military purposes. Each compartment I5-I4 can be designed to transporta large number of troops, or a smaller number if desired for the particular campaign undertaken. Tilting of the wing tips 29 with the plane traveling in close proximity to the ground will slow it down sufficiently to enable discharge of the troops without stopping the plane at a landing. The plane may be driven sidewise by one of the propellers 44 into a narrow space, for purposes of concealment or any other purpose. The manholes serve as means of escape if the plane comes down on water. Other uses also may be had, and obvious modifications may be made within the scope of the invention.

An arched cross-member 56 is supportedbetween the twin tails I3, as shown in Figures l and 3, and in the position shown it provides lifting support for the tails and the rear of the plane. It can be pivoted at its lower ends and mechanism can be provided, not shown, for swinging it about its pivot axis through an arc of about degrees between extreme positions extending vertically upward or vertically, downward. In 0r near the latter position this member would offer a tendency to keep the plane from nosing over while diving.

I claim:

l. An airplane having the rear tips of the wings thereof pivoted on a horizontal axis, a propeller mounted on each of said wing tips on an axis parallel with the axis of said pivoted mounting, means for tilting said wing tips, and means for rotating said propellers selectively at whatever angle at which said wing tips are pivoted.

2. An airplane having the rear tips of the wings thereof pivoted on a. horizontal axis, a propeller mounted on each of said Wing tips, means for tilting said wing tips, and means for rotating said propellers. l

3. An airplane having portions of the wing tips thereof pivoted on a horizontal axis, a propeller mounted on each of the said pivoted portions on an axis parallel with the axis of said pivoted mounting, means for tilting said pivoted portions, and means for rotating said propellers.

4. An airplane having the rear tips of the wings thereof pivoted on a horizontal axis, said tips having cut-outs therethrough, a propeller mounted on each of said tips within said cutout and having the axis thereof parallel with said pivotal mounting, means for tilting said tips, and means for rotating said propellers.

5. An airplane having the rear tips of the wings thereof pivoted on a horizontal axis at substantially right angles to the horizontal axis of the fuselage, a propeller mounted on each of said tips on an axis parallel with said pivotal mounting,

means for tilting said tips, and means for rotat ing said propellers.

6. An airplane having portions of the wing tips thereof pivoted on a horizontal axis at substantially right angles to the horizontal axis of the fuselage, a propeller mounted on each of said pivoted portions on an axis parallel with the axis of said pivoted mounting, means for tilting said pivoted portions, and means for rotating said propellers.

'1. An airplane having the rear tips of the wings thereof pivoted on a horizontal axis at right angles to the direction of travel of the plane, said tips having cut-outs therethrough, a propeller mounted on each of said tips within said cut-out thereof and having lts axisv parallel with said pivotal mounting, means for tilting said tips, and means for rotating said propellers.

s JOHN HEITMANN. 

